Study On Three-dimensional Geological Modeling Of Chang 6 Reservoir Group In Well A Area Of Wuqi Oilfield

The area A of Wuqi oil field is located in the south of wuqi county,the west-central part of Yishan slope of Ordos Basin.According to the previous data,the Chang 6 period is in the delta front and has good reservoir conditions,and the source rocks in Chang 7 oil reservior are abundant,indicating that the Chang 6 oil reservior of the A oil well has the potential for exploration and development.However,the development and evaluation of the Chang 6 oil reservior in the A oil well is relatively low,and the research of sand body distribution characteristics and reservoir attributes distribution regularity of the Chang 6 oil reservior are limited.Therefore,the 3D geological modeling of the Chang 6 oil reservior in the“A”oil well area is carried out in order to provide support for the development of oil fields.Stratigraphic division and correlation in the study area are carried out by means of identification of marker beds,cyclic control and correlation of stratum thickness,the Chang6 oil reservior was divided into five sublayers which are Chang 6₁¹?Chang 6₁²,Chang6₂¹,Chang 6₂² and Chang 6₃.The contour map of the top structure of the small layer reflects that the study area is a gentle monoclinic structure with High East and low west,and a small number of nosing structures are developed in it.The pretreated logging data are interpreted by interpretation model,the attribute parameters such as shale content,porosity,permeability and oil saturation of each well in the study area are calculated.Then the relationship among lithology,electrical property,physical property and oil-bearing property of reservoirs in the study area is further explored.Comprehensive analysis of existing research results and sedimentary facies indicators in the study area shows that the Chang 6 reservoir group in the study area is located in the delta front subfacies,and mainly develops underwater distributary channel microfacies and interdistributary bay microfacies.Among the sedimentary microfacies cross-well profiles of parallel and vertical provenances,underwater distributary channel microfacies of Chang 6₁²developed best,Chang 6₁¹,Chang 6₂¹ and Chang 6₂² took second place,Chang 6₃ is the worst.Comparing the sand-land ratio and sand thickness contour maps,it can be seen that the source of sediment in Chang 6 period mainly comes from NE direction,the rivers mainly inflow from the north and east of the study area,and outflow from the South and west.The sand body of Chang 6₁² is the best and Chang 6₃ is the worst.Based on the results of interpretation of logging data and the lithologic distribution characteristics in the study area,the intra-layer and inter-layer heterogeneity of the reservoir is explored.By calculating the evaluation parameters and comparing the heterogeneity of each small layer,it can be seen that the heterogeneity of the inner and interlayer of Chang 6reservoir group in the study area is as follows:Chang 6₂>Chang 6₁>Chang 6₃.Petrel software is used to establish structural model,lithofacies model and reservoir attribute model in the study area.A comprehensive analysis of the established model shows that:?1?There is a strong correlation between lithofacies model,reservoir attribute model and reservoir attribute model.That is to say,the high value area of attribute model corresponds well to the underwater distributary channel sand body of lithofacies model.?2?Among the Chang 6 reservoir group in the study area,Chang 6₁² is the best reservoir,followed by Chang6₂²,Chang 6₂¹ and Chang 6₁¹,and Chang 6₃ is the worst.